1. Field of the Invention
This invention relates to circuit breaker apparatus and more particularly to circuit breaker-alarm combinations automatically providing operator notification upon tripping of the circuit breaker.
2. Description of the Prior Art
Whenever a circuit breaker device trips, it is desirable and sometimes necessary to have an alarm produced which draws an operator's attention to the fact that a circuit breaker has tripped. Fusing devices have had this alarm feature for many years. However, with the advent of circuit breakers, alarm devices are generally mechanically linked to the circuit breaker and require installation at the time of manufacture. Such mechanically actuated alarms generally utilize a micro-switch in conjunction with the main circuit breaker contacts. However, if the circuit breaker primary contacts weld upon an attempt to trip, the alarm may not go off.
U.S. Pat. No. 3,689,801 "Circuit Breaker Including Improved Current Auctioneering Circuit", issued Sept. 5, 1972, to Engel et al. assigned to the assignee of the present invention, illustrates certain circuit breaker apparatus which typically would require a microswitch for alarm purposes, but already produces an output upon tripping or resetting of the circuit breaker. Such a circuit breaker is readily adaptable to the method taught in the present patent and is typical of many electronic circuit breakers in use today.
It is desirable to have an alarm device which is mountable at the time of manufacture or at a later date, in the field. It is also desirable to have an alarm which will energize regardless of contact welding; that is, when the trip unit signals the circuit breaker to trip, not being deenergized until the resetting of the circuit breaker.